WASHINGTON, Jan 22 (Reuters) - A key U.S. Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration’s decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

U.S., Japanese and French authorities are investigating two separate cases in which lithium-ion batteries on board the new airliner failed. One of the batteries sparked a fire in Boston, while the other forced an emergency landing in Japan.

All 50 Boeing 787s have been grounded as a result.

“Certainly the issues of FAA certification will be a key component of the aviation safety oversight hearing we’re planning,” an aide to the Senate Commerce, Science and Transportation Committee told Reuters in an email.

The aide, who was not authorized to speak publicly, said committee chairman Senator John Rockefeller was “following the situation surrounding the Dreamliner and FAA’s task force closely and he thinks the FAA and (Department of Transportation)are examining the issue carefully.” (Reporting By Andrea Shalal-Esa; Editing by Gary Hill)